My Dell Dimension E521 is totally non responsive none of the peripherals work. I get a blue screen saying something like " A problem has been detected and windows has shut down to prevent damages." It also says to press F8 select start up then select safe mode " and which none of that can be done..I got some sort of error code STOP: OX000000BE (Ox806CF800, Ox006CF121,OXF78A2788,OX0000000B)

Yipes - that's not good. Can you boot to the recovery disk that came with your computer?

Here's how: Insert the recovery disk and start the computer. Hit the F12 key to get to the Boot Menu. Arrow down to the CD and hit Enter.

If you can't boot to the recovery disk then you have a hardware problem. You can try swapping keyboard and mouse. You can also open the machine and pull a memory card. Just be careful doing that because in the low humidity, the card are suspectible to Electrostatic Discharge (ESD).

There may be a key that allows you to boot to a recovery utility. I'm not sure this machine has that option. When you boot, hit the F12 key and see if there's an option to boot to a recovery partition.